Laminates can be constructed by uniting two or more layers of material together. The process of creating a laminate conventionally refers to impregnating or applying an adherent material in or between layers of laminable material and treating the stack of laminable material to sufficient heat or pressure to join the layers of laminable material. The resulting laminate can take a wide and numerous variety of configurations including three dimensional forms which for example can have one fixed configuration, or can be configurable between two different configurations in which one of the two configurations is stable (“uni-stable configuration”), or configurable between two different configurations in which both configurations can be stable configurations (“bi-stable”). As an illustrative example, a uni-stable configuration may be disposed in substantially flat condition which can be then be disposed as a roll or coil. Upon extension of the laminate from the roll or coil, the laminate may transition toward and assume a stable tubular configuration with the edges disposed in opposed relation (whether adjacent or a distance apart) to define a slit along the longitudinal axis of the tube (also referred to herein as a “longitudinally slit tube”).
The laminable material may include one or more of a wide variety of discrete or woven fibers. As illustrative examples, the fibers can include: boron carbide fibers, silicon carbide fibers, alumina fibers, alumina titanium fibers, carbon fibers, para-aramid fibers such as KEVLAR®, polypropylene such as INNEGRA®, a ultra-high molecular weight polyethylene such as DYNEEMA® or SPECTRA®, s-glass, e-glass, polyester, or the like, or combinations thereof. The laminable material can be coated or impregnated with an amount of adherent having mechanical characteristics compatible with altering configuration of the laminate between the substantially flat condition and the longitudinally slit tube. As illustrative examples, the adherent can include: a phenolic, an epoxy, a polyethylene a terephtalate, a vinylester, bis(maleimide/diallybisphenol A, a cyanate ester, a nylon, a polypropylene, polyethylene terephthalate, polyester, polyaryletherketone (such as PEEK®), acrylonitrile butadiene styrene, a polyamide, a polyethylene, a thermoplastic urethane, or the like, or combinations thereof, which can be either catalytically or thermally set.
Because the resulting laminate includes discrete or woven fibers, the fibers may to a lesser or greater extent be exposed, become exposed or fray at one or more of the laminate edges. This may be exacerbated in longitudinally slit tubes which may be disposed between a first configuration and a second configuration or which may be rolled and unrolled to retractably extend a deployable laminate structure. In certain instances, the fibers disengaged from the laminate can extend outward or detach from the laminate to entangle in or damage the deployment device from which the deployable laminate structure retractably stows.
Additionally, because longitudinally slit tubes often deploy from a first condition in the form of flat laminate extended from a roll or coil to assume a second condition in the form of a longitudinally slit tube, the tubular form may not have adequate resistance to deflection along the longitudinal axis under load, or may not have adequate resistance to radial surface deflection upon application of radial forces, or may not have adequate resistance to torsional deflection of the tubular form due applied torque or twisting about the central longitudinal axis of the tubular form.